1. Field of the Invention
This invention pertains to a propulsion device for watercraft. More specifically, this invention pertains to an arrangement of nested foils that provide an efficient means of propulsion for watercraft.
2. Description of the Prior Art
It is known to utilize foils or blades in order to produce propulsion devices. See, for example, my U.S. Pat. Nos. 3,204,699, 3,122,759, 3,204,262 and 4,178,128. These all describe devices for providing propulsion with the use of foils and are extremely successful. The first three patents describe devices that produce a wake or a wash whose momentum and energy are not fully utilized. The fourth patent describes a nested foil arrangement which more fully utilizes the transverse component of the wake energy to provide for more forward thrust. The principles taught in the fourth patent have been utilized to devise a propulsion device that not only utilizes the transverse component of the wake energy, but also, through its unique configuration provides efficient propulsion with a minimum of aeration.